Perhaps I wasn't paying enough attention to this fork's commits, but what is actually happening with the birth date and where does it go?
This information is supposed to be passed by browsers to the sites you visit, so that they would implement age verification.
The systemd maintainers are among the first who have rushed to be compliant with the new law, even if compliance with abusive laws does not seem the right solution. In the so-called land-of-the-free, any law that commands people how to use their own property in circumstances when what they do cannot affect in any way other humans, should have been struck down as anti-constitutional. Laws might require Web sites to have some kind of age verification, but they may not decide what people can or cannot run on their own computers.
If the legislators were so concerned about age verification, there are easy and non-invasive solutions, like providing a way for each adult to obtain (without recording this transaction) a device that generates one-time codes for age verification (like they were used for online banking before the current fashion of using smartphone apps). Or if that is too expensive, some printed cards with a list of codes with temporary validity could be used, or other such methods that can verify age without providing user identity. Even such methods are worse than the right solution, which is to use parental controls instead of age verification at the sites.
The requirements of the law are incredibly stupid and for now they are trivial to circumvent, but the fear is that this is only the beginning. After the legislators see that they can force anyone to work to implement such ridiculous demands, they will demand more, eventually leading to privacy-restricting measures that will no longer be easy to circumvent.